Whilst psycho-educational interventions have been shown to be effective in some LMIC, their availability in most of LA is low. We are proposing to develop and test a brief and low-intensity psycho-educational intervention to treat people with depression and a co-morbid chronic medical condition (hypertension and/or diabetes) recruited in general medical settings. The depression intervention (CONEMO) will be delivered via mobile phones using mostly message services (SMS; text), with the support of a booklet as a technology bridge and an auxiliary nurse to provide motivation, monitor treatment progress, and assistance with using the program. The auxiliary nurse will be assisted by a web-based automated interface. Most of the first two years of this proposal will be dedicated to develop CONEMO, including all the messages, decision algorithms, usability and field testing with potential users, an nurse interface. The end product of this process will be the CONEMO system ready to be used in the trials. There will be a pilot study before the trials to ensure the trial methodology to be used, including an improved case-identification for recruitment, is feasible. The intervention (CONEMO) will be tested in randomized controlled trials comparing usual care plus CONEMO to usual care alone, evaluating effects of the CONEMO program on clinical and other outcomes and treatment costs in Sao Paulo, Brazil, and Lima, Peru. We are aiming to recruit a total of 851 people from 20 primary care clinics in Sao Paulo using cluster randomization. In Lima randomization will be at an individual level and we plan to recruit 421 individuals in two large medical out-patient clinics in general hospitals. The primary outcome will be the proportion of people with no clinical depression (PHQ-9 <10) at 3 months after enrolment into the trial. Other outcome measures include PHQ-9 at 6 months after enrolment; functioning levels; and quality of life. The analysis of data will be in accordance with CONSORT guidelines, with primary analysis on an intention-to-treat basis. Extensive dissemination activities are planned to be implemented during the last two years of this grant with the aim of scaling the intervention if proven successful.